PASTRY: Place flour, sugar and salt in a medium size mixing bowl. Cut in
the chilled butter, then rub mixture with your finger tips until it
resembles coarse crumbs. Sprinkle with the vinegar and shape gently into
dough. Press dough into an ungreased 9-inch round cake pan to a thickness
of about 1/4 inch. The crust should be worked to 1 inch up the sides of the
pan.

FILLING: Place the 3 cups of blueberries on the crust. Mix the sugar and
cinnamon into the flour and sprinkle evenly over the berries. Place in the
oven on the lowest rack and bake for 50 minutes or until the crust is
golden and the filling bubbles.

Remove from the oven and immediately sprinkle with the remaining 2 cups of
blueberries. Let the kuchen rest at room temperature for about an hour.
Then sprinkle with the powdered sugar and serve.